This invention generally relates to systems and methods for deinterlacing high-definition and standard definition video using adaptive techniques for spatial and temporal motion.
Video is often interlaced in order to improve picture quality and decrease the bandwidth required for transmission. Interlaced video formats provide one half of the lines in an image for any given frame—the odd-numbered horizontal lines of the frame may be displayed at one instant, while the even-numbered lines of the frame may be displayed the next. Each set of lines can be referred to as a field. In order to display the video in progressive, or noninterlaced, format, interlaced video must be deinterlaced. Deinterlacing requires the derivation of the missing set of lines for any given field.
One deinterlacing technique known as film-mode deinterlacing takes advantage of film content's 3-2 cadence to create 60 perfect full frames of video per second. A cadence refers to a pattern of successive fields. Another deinterlacing technique known as video-mode deinterlacing employs single-mode interpolation, weaving, vertical interpolation, motion adaptive deinterlacing, or a combination of such techniques to process video content to create 60 full frames of video per second. Video-mode deinterlacing often results in undesirable artifacts in the video. These artifacts include line flicker, Moire, or aliasing. Such artifacts may be marginally noticeable on moderate sized televisions, such as televisions that are 42-inches in size or smaller, that display video at lower resolution formats such as 480i or 720i. However, displaying video on televisions that are 42 inches or larger in size and capable of displaying resolutions of 1920 by 1080 pixels can cause these artifacts to be more visible.
Typical deinterlacing schemes for high-definition television deinterlace mixed-mode content, or film content that includes text content, with video-mode deinterlacing rather than film-mode deinterlacing. This use of deinterlacing may cause the text to appear blurred, or feathered, and may introduce artifacts such as line flicker and Moire. Further, known deinterlacing schemes for high-definition television provide single engines for processing motion. This deficiency may cause portions of video to be deinterlaced using suboptimal techniques.
In view of the foregoing, there is a continuing interest in providing a robust deinterlacing scheme that provides high-quality video on displays of all sizes and resolutions.